“This election will probably have the biggest contrast that we’ve seen maybe since the Johnson-Goldwater election, maybe before that,” Obama told donors at the first of three campaign events in this battleground state. The events were expected to raise at least $1.7 million.

In his 1964 race against Goldwater, Johnson carried 44 of 50 states and won 61 percent of the popular vote, the largest share of any candidate since 1820.